In many process industries, such as chemical plants, nuclear generator facilities, etc., it is necessary for process piping to pass through the walls of containment structures. Where it is important to prevent the escape of toxic fumes, radioactive gases or the like, steps are taken to provide caulking or sealing means between the wall of the containment structure and the outer wall of the pipe. Routinely, such seals, hereinafter referred to as penetration seals, must accommodate some relative movement between the pipe and the containment structure, to allow for expansion and contraction. The seals provided for this purpose are known and do not form part of this invention.
To ensure the integrity of the penetration seal, it is desirable from time to time to test the seal by placing it under relative pressure from one side of the containment structure to confirm the absence of leakage flow. This is a fairly simple procedure where the joint is designed to withstand only relatively low pressures. However, when the joint must stand relatively high pressures, the testing procedure becomes more complex and difficult, because the testing equipment itself must be built to withstand the test pressures employed.
In accordance with the present invention, a novel sleeve structure is provided, which enables a pressure containment chamber to be provided at the area of penetration of the pipe through the wall of the containment structure. The pressure containment chamber enables the requisite high pressures to be imposed upon the penetration seal, in order to establish its integrity.
Inasmuch as the need or desire for integrity testing of the penetration seals generally arises after completion of the structure, it is frequently necessary to install the pressure containment chamber after installation of the piping. One of the significant aspects of the present invention, is the design and construction of a high pressure pipe sleeve arrangement which can be installed about the process piping after installation thereof and which provides a highly effective, economical structure for the containment of relatively high pressures, so that the ability of the penetration joint to withstand such pressures with integrity can be established.
Pursuant to the invention, inner and outer collar assemblies are provided for mounting respectively on the process piping on a penetration sleeve which surrounds the piping and forms the access opening through the wall of the containment structure. The respective collar assemblies are adapted to lockingly interfit with each other so as to define and annular wall spanning the annular region between the process piping and the penetration sleeve. Because of expected eccentricities between the axis of the process pipe and the axis of the penetration sleeve, the interfitting relationship of the inner and outer collar assemblies is itself designed to accommodate eccentric positioning of the central axis of the respective assemblies.
The interlocking collar assemblies form, together with the process pipe and penetration sleeve, a containment housing, which is closed at one side by the penetration seal to be tested. An elastomeric collar, designed for wrap-around field installation at the penetration joint, extends from a projecting end of the penetration sleeve to and into close fitting contact with the outer wall of the process pipe. At each end, the elastomeric sleeve is engaged by inflatable clamping rings, which surround the ends of the elastomeric boot and serve to tightly clamp the boot at each end to the process pipe or penetration sleeve, as the case may be. The inflatable clamping rings are contained on the outside by cylindrical wall portions of the respective collar assemblies. Accordingly, when the rings are inflated, they expand inwardly, tightly sealing the opposite axial ends of the elastomeric boot. Surrounding cylindrical walls of the collar assemblies serve, together with the interlocking annular end wall portions, to provide direct support for the elastomeric boot, in the region between the clamped ends thereof.
Pursuant to the invention, the collar assemblies are provided in segments, preferably semi-circular, which are applied over the process pipe and penetration sleeve from opposite sides and then secured together to form a continuous annular housing sleeve. After being mounted in position, the collar assemblies are securely bolted together.
Pneumatic pressurizing valves are provided for each of the clamping rings, to enable them to be pressurized after the sleeve parts are secured in position. Likewise, a pneumatic pressurizing valve is provided in the elastomeric boot, which projects out through the sidewall of the surrounding sleeve, enabling the chamber, enclosed by the elastomeric boot, to be subjected to a substantial pneumatic pressure, in order to test the penetration seal. The elastomeric boot is formed with a bellows-like convolution formed in a radial end wall, which extends from the process pipe outward to the diameter of the penetration sleeve. This convolution accommodates any eccentric relationship of the center line of the process pipe with respect to that of the penetration sleeve without undesirably stressing the material of the boot.
For a more complete understanding of the above and other features and advantages of the invention, reference should be made to the following detailed description of a preferred embodiment and to the accompanying drawings.